🔗 Share this article

PHEVs release nearly five times more global warming pollution than lab-reported data indicate, as per a new analysis.

Widening Gap Between Lab and Actual CO2 Output

Data shows that PHEVs emit only one-fifth less CO₂ than conventional gas and diesel vehicles, based on analysis conducted by a non-profit group. That contrasts significantly with lab tests, which suggested a three-quarters decrease in emissions.

Researchers examined information from onboard fuel consumption meters of eight hundred thousand cars registered in the EU from 2021 and 2023. The team found that actual CO₂ emissions from PHEVs in 2023 were nearly five times higher than lab estimates, increased from 3.5 times in 2021.

“Actual emissions are increasing, while lab-reported emissions are falling,” said a lead analyst involved in the study. “This discrepancy is growing and creates a significant problem. Consequently, PHEVs emit almost as heavily as petrol vehicles.”

Primary Factors Behind the Emissions Gap

Analysts attributed most of the difference to overestimates of the “utility factor” – the percentage of miles driven in battery mode compared to total mileage. They determined that only 27% of driving was completed in EV mode, whereas official estimates suggested 84%.

Even, when running in EV mode, pollution levels were well above lab projections. This occurred because EV motors were not strong enough to function alone, leading to engines burning gasoline for nearly a third of the distance completed in EV mode.

Policy and Financial Consequences

Based on calculations, the lowballing of PHEV emissions enabled four large carmaker companies to avoid over €5bn in fines between 2021 and 2023, by artificially simplifying adherence with European Union fleet-average CO₂ standards.

Furthermore, drivers of PHEVs could spend about €500 more annually in operating expenses than is assumed under laboratory tests.

“The strong claims that manufacturers like to make about their plug-in hybrid vehicles are clearly far from the truth,” commented a transport analyst. “Consumers are being duped into believing that by purchasing a PHEV, they are helping the planet and saving money. Actually, PHEVs are little better than standard petrol and diesel cars in terms of energy use, CO₂ production, and operating costs.”

Political Debate and Automotive Lobbying

Hybrid vehicles have lately been drawn back into political discussions as automakers have pressed the European Union to weaken CO₂ targets. A proposed ban on new combustion engine vehicles in 2035 has faced heavy lobbying from the car sector and opposition from EU countries with significant car industries.

Some senior politicians have proposed plug-in hybrids as a possible “flexibility” option to introduce in the legislation.

One independent energy policy expert, who was not involved with the study, called the report a “very useful contribution” after a long period in which parts of the automotive sector argued there was too little data to accurately evaluate real-world CO2 output.

“These findings show, beyond any doubt, that the gap between official and real-world PHEV energy use and CO₂ output is significantly larger than for gasoline or diesel cars,” they stated. “All policy adjustments concerning PHEVs should be made with utmost caution and in the light of that data.”